hugo module cache error preventing site from building locally

[olizilla]

About every other week, I am hitting an issue where the sites fails to build locally, failing with an error about missing modules.

⨎ npm run serve

> specs-new@1.0.0 serve /Users/oli/Code/filecoin-project/specs
> hugo server --bind=0.0.0.0

go: github.com/filecoin-project/specs-actors@v0.8.6: reading github.com/filecoin-project/specs-actors/go.mod at revision v0.8.6: unknown revision v0.8.6
hugo: collected modules in 768 ms
Error: failed to download modules: go command failed: go: github.com/filecoin-project/specs-actors@v0.8.6: reading github.com/filecoin-project/specs-actors/go.mod at revision v0.8.6: unknown revision v0.8.6

The fix

hugo & macos can't play nice with their tmp dir. you have to delete it all and start again.

npx hugo mod clean --all

This will wipe the hugo module cache, so it can be downloaded fresh next time you run a hugo command (or npm run serve)... you need the --all flag in there or else it seems that the clean command (as with all the others) fails when it encounters the broken module.

---

The hugo author notes that this should be more promenant in the docs... no kidding.

A related hint from me (which should get a more prominent place in the docs):

• Hugo uses a /tmp dir for the cache if cace dir is not set (in config.toml or environment)
• Go downloads the modules and write protects all directories
• On MacOS I have experienced some occasional issues which I guess relates to MacOS trying to clean out these directories, but only partly succeeds.
• Setting HUGO_CACHEDIR os env variable to something outside /tmp is the solution to the above. It’s also in general a good thing.

see: https://discourse.gohugo.io/t/hugo-modules-for-dummies/20758/8

I dont see how manually managing your cache dir is a good thing, but i've wasted enough time on this now, and passing the --all flag seems to fix it without having to pick a custom tmp dir that works on all OSs /rant

[yiannisbot]

@olizilla that's very useful! I think it should be in the main README, as people will likely not search through issues to troubleshoot their local build.